Glow relay tube



g 1932- H. c. RENTSCHLER 3,375,315fl GLOW RELAY TUBE Original Filed Feb. 7, 1928 INVENTOR .H. C.PENTSCHLER ATTORNEY Patented Aug. 30, 1932 STA'IES 3 AT f HABVEY OLAYTON RENTSCHLEB, OF EAST ORANGE, NEW JERSEY, ASSIGNOR 'JJO WEST- EQ'GEOUSE LAM'I COMIANY, A CORPORATION 0F IEENNSYLVANIA.

GLOW RELAY TUBE 011 application flled February 7, 1928, Ser1al N0. 252,437.

Divided and. flli3 application :flled Mareh 7 27, 1929. Serial N0. 350,164.

This application is a division of application Serial N0. 252,437, Rentschler filed February 7 1928 and entitled Glow relay tube.

This invention relates to an electrical discharge device of the gaseous conduction type and more particularly to such a device in which the discharge takes platte between cold electrodes in a gaseous atmosphere at a reduced pressure.

One of the objects of this inventmn 1s to provido a gaseous conduction discharge device having extremely sensitive means for controlling the discharge therethrough.

Another object is to provide a gaseous couduction discharge device capable of deliv er ing relatively large currtants and havmg means operated by extremely feeble current changes for controlling the discharge.

A further object is to provide a gaseous conduction device which normally interposes a high resistance to the Passage of current therethrough at a predetermined voltage and which has means operative by extremely fee bis currents in a supplementary circuit for reducing such resistance so as to permit a -reiatively large fiow o:f current at said predetermined voltage.

A still further object is to provide a gase-.

ous conduction relay which Will operate at relatively 10W voltages .and which is extremely sensitive to current changes in a supplementary circuit.

Other objects an d advantages Will hereinaf'ter appear.

It is we]l known that the voltage required to initiate an electrical discharge in a g1ow discharge device is higher than that required to niaintain the discharge once it has started.

Thus, for instance, in voltage regulators, alternating current rectifiers, lamps, etc. employing spaced apart electrodes in a gaseous atmosphere and operating in the absence of thermionie emission, by a proper choice of electrode materials, electrode space, gas pressure, etc., the discharge may be made t0 statt at a otential of around 120 volts, while the discharge once started Will continue at otentials as 10W as 85 to 90 volts, depending somewhat upon the current passing through the tube. This difl'erence in starting and. op-

erating potential is due largely to the high resistance imposed by the cathode dark space. Upon initiation o:t' a discharge in the device, this resistance layer is broken dovvn and permits the discharge to continue 011 a, voltage lower than the starting otential or another independent discharge to be started at a materially lower voltage.

It has also been found that there is a definite spacing of the electrodes for a particular gas and a, particular pressure thereof at which the voltage required to initiate the discharge is a, minimum. Moreover, vvhereas, devices of this natura may rezidily carry currents up to several hundred milli-amperes, the amount of current required to start the discharge is exceedingly small, that is, in the natura of only a few micro-amperes.

1 may use of the above phenomena for the production of a sensitive glow relay tube and in accordance with my invention I provide such a gaseous conduction device having a cathode of relatively large area and a main anode and control anode of sma.ll areas. The ma.in anode is so shaped and positioned with respect to the cathode that a oonsider'ably higher voltage is required to start a. discharge between said electrodes than is available, whereas, the control anode is difierently positioned with respect to said cathode and is so constructed that a discharge may be im'tiated between said control anode a.nd the cathode at a cons'iderablj lower Potential than that required to start the discharge from the main anode.

In the specific embodiment illustrated hereinafter, the control anode is positioned at the critical distance from the eathode at which the minimum voltage is required with the particular gas at the pressure employed to start the discharge to the cathode. The main anode is arranged at a suflicient distance from the cathode t o prevent the starting of a discharge therefrom except at materially higher voltages. As a consequence of this construction, if a predetermined voltage is impressed between the main anode and cathode, be1ow that necessary to initiate a discharge therebetween but suificiently high to maintain such discharge once it has started und if second source of potentisl is applied between the contro l anode and cathode of suflicient otential to initiate a d1scharge between said electrodes in responsc to some external condition, the ma.indischarge may be started through the initiation of the discharge from the control anode. Since only a very feeble current is required to inilsiate this auxiliary discharge, such as that obta1ne d from a photo-electric cell, it is possible in th1s manner to cause such feeble current change t o ereate a current flow of much greater magn1- tude in the circuit containing the main anode und cathode.

In order that the invention may be more fully understood, reference will be had to the accompanying drawing in which:

' Fig. 1 is an elevation, partly in section, of a tube employing my invention associated with electrical apparatus for controlling the operation thereof;

Fig. 2 is an elevation, partly in section, of a modified form of electrode arrangement; and

Fig. 3 is a, sectional view on the line 3-3 of Fig. 2.

The device shown in Fig. 1 comprises an envelope 1 containing a cathode 2, main anode 3 and cqntrol anode 4. The electrodes 2, 3

and 4 are suitably supporte by a. press 5 und. a16 joined tq leading-in wires 6, 7 and 8 respectively. A metall1c projection 9 extends outwa'rdly from the cathode 2 into p1r0ximity to the control anode 4. The space be- 8l5 twecn the control anode and the end of the pr0]ection 9 should be such as to enable the minimum otential to be obtained for starting the discharge between the electrodes 2 und. 4. This distance is dependent upon the paro ticular gasemployed und. the pressure thereof.

For instance, with a filling 015 argon gas at a pressure from 5 to 8 millimeters o;f mercury, a spacing of approximabely 1 mm. has been :Eound t0 give the requisite 10W otential startingcondition. I:E other pressures are used 01 other gases employed, it may be necessary to vary the spacing of the control anode from thc cathode.

The main znode 3 is spaced a much greaten distance from the cathode than the control electrode. In the practical embodiment of the invention employing the gas pressure specified above, excellent operatihg characberistics Ware obtained with a cylindrical cathode 2 of 1 inch in diameter having the main anode 3 located at the axis thereof. In arder to reduce the starting and operating potentials of the device, an electro-positive metal, such as one of the alkali metals or alkaline earth metals or a, lass volatile metal such as 5 alkali metals are more suitable.

The main anode 3 is joined to one side of an alternating current line 10 through a, couductor 11 und. the cathode 2 is joined to the other side of said line through Conductor 12.

An electro-magnetic relay 13 is interposed in the ]ine 11 so a.s to be operated when a. discharge is created between the electrodes 2 und 3 of the device The resistanoe 00 eur- 15 limits the current which may pass between the electrodes 4 und 2 to a. small valu'e. The voltage of the line 10 is such that when the switch 16 is closed, the small current passing the resistance 15 at 10W voltage Will starb a. discharge from the control anode to the cathode, thus ioniz'ing the gaseous filling and breaking down the cathode'resistanceL Immediately this occurs, thc resistance between the main anode 3 and the cathode becoma sulficiently decreased 170 ca.use a discharge therebetween, thus permitting a relatively heavy current to fiow through the line 11 and the winding of the rlay 13. This operates the switch 17 and energizes the circuit 18 for any desired purpose.

In the embodiment shown in Fig. 1 tha switch 16 may take the form 0f a. bi-metallic thermostatic element which, upon attaining a predetermined temperature closes or opens, thereby starting or stopping the discharge from the main electrodes und. rendering available relatively heavy currents for operating the relay 13 without necessitating the passage of such relatively heavy current directly through the switch 16.

Fig. 2 illustrates a modified form of relay in which the control anode 4 is provided with a head 19 of a material which is more active than that of the electrode 3.

F01 instanoe, electrode 3 may be composed of a metal such as nickel and the anodehead 19 of a material such as thorium, titanium or uranium which has the property of still further decreasing the potential required 130 initiate a discharge. In this manner the differential of otentials required to start the main und control or trigger discharge is increased. The active material constituting the control anode hea.d 19 also exercises -a clean-up acti0n or gas 'purifying eifect to maintain the gaseous filling in a more pure condition. -If desired, the anode head' may be coated with barium oxide which is reduced by the thorium 0r other active material, to liberate barium metal. The barium metal vaporizes onto the surfaccof the cathode 2 and serves to maintain the cathode drop of this electrode at a lpwer value.

While I have shown several applications of my invention, it is to be understood that it may be employed in other connections for various purposes and that the details of coustruction may also be varied within wide 'limits without depaflsing from the invention.

What is claimed ist A glow discharge relay device comprising as compare 130 the distance between said main anode and said cathode.

In testimony whereof, I have hereunto subscribed my name this 22 day of March, 1929.

HARVEY CLAYTON- REN'I'SCHLER. 

